Wednesday, 25 June 2014

Rockabill Nest Census 2014 - Roseate Record Reached?

So we've been a bit quiet on the blog over the last week - sorry for that - though some of you might have seen/heard us on the RTE Six-One News on Monday and The Star tand 2FM today, proving that we're alive and well! The reasons for the lack of regular updates have been twofold - the first being that the huge number of eggs we alluded to in previous posts are now turning into huge numbers of chicks! So that means we have hours of counting, measuring and ringing to do every day. It's amazing to see how quickly the chicks grow, how they interact with their siblings, and how protective their parents are - but it's also tiring trying to keep tabs on all of the above!

The other reason for the lack of updates is because over the last ten days or so we carried out our full-island nest census - seeking out and counting every single nest and clutch on the Rock and the Bill, and repeating the whole thing again a week later. To say that it was exhausting would be an understatement, but from all that hard work we can tell that it's looking like a pretty good year on Rockabill. The results are still provisional at the moment (we have one of the Roseate Terns crunching the numbers for us again...), but here's what the breeding numbers for each species on Rockabill this year look like at the moment:

Roseate Tern - the Rockabill breeding population has increased slightly this year, which is good news for the species in Europe! (Picture taken under NPWS license)

 Roseate Terns
First of all it bears repeating that the Roseate Tern is one of the rarest breeding seabirds in Northern Europe. Rockabill is the single biggest breeding site for Roseate Terns in Europe and we have around 80% of the Roseate population of Ireland, the UK and France here on this one little island, so needless to say what happens on Rockabill is pretty important! A lot of hard work has been put in over the last twenty-five-plus years and for much of that time the population here has been increasing - from 180 pairs in 1989 to over 1,200 in 2013 -with numbers levelling out over the last few years. This year we're happy to report that it has again been a good year with close to 1,250 pairs of breeding Roseate Terns - a new record that's slightly above last year's total. It's a small increase, but good news nevertheless! Nestbox usage has been good again, with a large number still going for more natural sites in the shelter of vegetation, rocks or in between nestboxes!

Common Tern - very common on Rockabill! (Picture taken under NPWS license)

Common Terns
As with the Roseates, the number of Common Terns has been generally increasing for the majority of the last twenty-six years and remained in the region of 2,000-2,200 pairs in recent years. Well we're happy to report that we have close to 2,150 pairs this year - not a Rockabill record, but very good all the same and more good news for breeding Terns and Seabirds in Ireland this year.

Arctic Terns
Arctic Terns have always bred here in smaller numbers than the others - they breed in bigger numbers on the west coast. In 2009 there were over 350 breeding pairs here, many of which were located on the Bill, but they have declined dramatically since. Unfortunately this year the Arctics have been the victims of repeated predation by Herring  Gulls and there are few if any left on the Bill, with the smaller colony by the helipad suffering a similar fate. We suspect a small number of pairs may be scattered around other parts of the island, but it remains to be seen how successful they will be.

Severe storms over winter have had a devastating effect on our Black Guillemots. (Picture taken under NPWS license)

Black Guillemots
On our first week here we got up at 7am every morning to count the number of Black Guillemots on and around the island to give an indication of how many were likely to breed here over the summer. Unfortunately the severe storms over the winter had a pretty devastating impact on our Auk species (Guillemots and Puffins) and a number of Black Guillemots born and ringed on Rockabill were found dead along the coast in Dublin and Northern Ireland. As expected their numbers are way down this year with only around 50 pairs breeding here, compared to 90 or so nests for each of the last three years. Fingers crossed most will manage to successfully fledge young this year, and that the coming winter is better than last - though with extreme weather events expected to be more common as climate change progresses, it's hard to predict how populations of species like Black Guillemots will fare here in the future.

Kittiwakes in "Kitti-City" on Rockabill. (Picture taken under NPWS license)

So far we've had good news regarding Roseate and Common Terns, and bad news about our Arctic Terns and Black Guillemots - what about the Kittiwakes? Well they're doing ok - they've had better years but they've had much worse too! We have around 150 pairs this year. Numbers last year were low, but our count this year is not too different to most of the previous year's. From our census it appears than the average clutch size is a little higher than expected, so hopefully that bodes well for the future.

So that's the (provisional) results of our nest census on Rockabill for the 2014 season - the good, the bad, and the! It's important to remember that those counts are just of nests and breeding pairs - this isn't the end of the story. The chicks have started to hatch over the last week and it'll be late next month before they'll fledge, and needless to say a lot can happen over those few weeks - predation, disturbance, food shortages, disease and (probably most significantly) severe weather might all yet have  say in whether or not 2014 is considered a good/successful year for the breeding seabirds on Rockabill. But so far so good!

We'll keep you updated! In the mean time, spare a thought for us during what is the part of the breeding season that all of those Common Terns are at their most aggressive!

 - Brian & Donnacha

Tuesday, 17 June 2014

Rockabill's first Roseate Chicks of 2014

Only a day after we had our first two Common Tern chicks hatch yesterday, we had our first Roseate Chick hatch today! Not only that, but we had our second, our third, fourth and fifth Roseates hatch too!

Here are the Common Tern chicks today - they've 'fluffed' up a bit and have been looked after by their parents all day.
One of the first Common Tern chicks getting it's wing measured. (Picture taken under NPWS license)

Rockabill's first Common Tern chicks of 2014 - they've fluffed up a bit since yesterday! (Picture taken under NPWS license)

And here are some of today's Roseate chicks!  Rockabill holds over 80% of the North-West European population of Roseate Terns, so it's critical that they're monitored and conserved here - fingers crossed it will be a good year!

A Roseate Tern chick hatching out of it's egg tonight - you can see the little white egg tooth used to help it break out. (Picture taken under NPWS license)
Roseate Tern chick being weighed on 'Day Zero' (Picture taken under NPWS license)

The first Roseate Tern egg we found was in this nestbox - and this is what greeted us on our rounds today. (Picture taken under NPWS license)

Another Roseate Tern chick being weighed - this one is at least half a day older than the one above. (Picture taken under NPWS license)

So the floodgates have opened in terms of Tern chicks hatching on Rockabill. There must be something in the air this week because the guys on Kilcoole beach had their first Little Terns hatch in the last few days too (see their blog here)! Needless to say hatching is only the first step and it'll be the middle of next month before these guys fledge, but hopefully the next few weeks will be good food and weather wise for the chicks (and the wardens)!

- Brian & Donnacha

Monday, 16 June 2014

First Tern Chicks of the Summer!

 It's been over three weeks since we found the first Common Tern egg on the island (see here) and we were expecting our first chicks at the end of this week - Common Terns hatch after around 22 days, but the Terns were a bit unsettled a few weeks back so we thought that might slow things down - apparently not!

We knew what clutch we found first, and that it was being incubated and hadn't been abandoned or predated or anything like that - and on our way down to check on an area near the Bill we were suprised and delighted to see our first small fluffy chick! And on our way back around half an hour later we were even more surprised to see our second chick! The second chick was a lot less fluffy having just hatched, but will look different tomorrow.

The first Common Tern clutch laid on Rockabill this year. (Picture taken under NPWS license) 
The first Common Tern chicks to hatch on Rockabill in 2014. The chick in the foreground is only a few hours old and hence less 'fluffy' than it's sibling - though that will change by tomorrow. (Picture taken under NPWS license)

Despite being the younger of the two, the closer chick was a lot more active than the one at the back which just seemed to want to rest! (Picture taken under NPWS license)

Rockabill's first Common Tern chicks of 2014. (Picture taken under NPWS license)

So they are our first Common Tern chicks of the year - the first of a few thousand!! We'll keep you updated on their progress and development, as well as any more chicks we find over the next few days.

- Brian & Donnacha

Saturday, 14 June 2014

A preview of the Big Count!

Over the last three days we've carried out the annual nest census - systematically finding, counting and marking every single nest/clutch of every species on Rockabill - that means every patch of ground, every nestbox, every hole in a wall and under every bit of vegetation! Thankfully the weather was on our side which made the whole thing a little bit easier.

In our daily checks of the study areas we've noticed the number of new nests appearing has slowed considerably - most pairs have laid eggs now so it's the perfect time to do the nest census. Doing it now also means we should avoid counting any late nests, which are treated separately in our results as they are often laid by young inexperienced Terns and so their clutch size and productivity is generally lower than the main population. Doing it now also means we should minimise the chances of including re-laid clutches in our results, which could otherwise create some bias in our results.

Common Terns usually lay 2-3 eggs - this is a 'super-normal clutch' with 7 eggs (and an 8th was added later!) - it's likely to be the result of two females laying in the same place and putting their eggs together, and probably 'stealing' another egg or two that they thought might ahve been theirs. (Picture taken under NPWS license)

We have thousands of Terns here, and a lot of Kittiwakes and Black Guillemots too, so we have a lot of adding up to do over the next couple of days. We'll also be doing another count of everything at the end of this coming week, but we should have some provisional counts to share in the next few days to give a snapshot of how things are faring here compared to previous years - so keep an eye out for that blog post over the next few days. As a bit of a teaser I can also tell you we found our first chicks of the year during the census - so stay tuned!

And finally, we had a visit from some Porpoises - a mother and calf, and another adult - who were obviously enjoying the calm conditions over the last few days!

Harbour Porpoises - a mother and calf - paid us a visit during our census!

Keep an eye out for our nest census update in the coming days!
Until then!

- Brian & Donnacha

Saturday, 7 June 2014

Uncommon Tern Nesting Places!

So as we've mentioned in some recent posts, there are currently eggs EVERYWHERE on Rockabill! We've been doing twice-daily counts of our 9 study areas and are seeing increases every day in the numbers of Roseate and Common Terns in each one of them.

Now Roseate Terns like to nest in shelter, so their nests are confined to either nestboxes or in a bunch of vegetation or under a shrub of some sort (usually Tree Mallow). That's what it says in the books and our Roseates have obviously read the same books - if you look around the island they have nests exactly where you'd expect them to!

Roseate Tern eggs laid under shelter (Pictures taken under NPWS license)

Common Terns on the other hand are much less fussy. Basically, find the right island/lake/shore and they'll be absolutely everywhere there! If there's a bit of sand or mud they can scrape a little hole into they'll happily settle there - if there isn't, well they'll probably settle there anyway! Here's some of the more unusual place we've also found their eggs so far......

There's one nesting in some debris in a dried-up drain.....
Common Tern nest in a dried-up drain! (Picture taken under NPWS license)

There's a nest at the base of these steps....

....and at least 5 seperate clutches around these steps!

This looks like a fairly natural nest......
(Picture taken under NPWS license)

........until you zoom out and realise it's on an old moss-covered floor mat!
(Picture taken under NPWS license)

Firepoint - the location of emergency fire equipment...and two clutches of 3 Common Tern eggs!

A clutch of 3 Common Tern eggs, either side of our firepoint sign! (Picture taken under NPWS license)

And the 10+ foot high wall behind Firepoint? That has clutches on top of it too!

One of several Common Tern nests on top of a very high wall! (Picture taken under NPWS license)

They're big fans of renewable energy too, nesting in behind these solar panels:

Common Tern nest around the back of the solar panels. (Picture taken under NPWS license)

They're not too worried about getting in our way either! Here's one quite literally just outside one of our hides - and it's not the only one!
Common Tern nest, picture taken from inside our hide to show just how close it is! (Picture taken under NPWS license)


And lastly, we had worried that the wording of this sign might lead to some confusion on the birds behalf, but apparently not:

Roseate Tern egg behind the sign (Picture taken under NPWS license)

So when we say they're nesting everywhere, we mean EVERYWHERE! Any patch of bare ground, behind plants on sloping rocks, between cracks in rocks, on the paths, on ledges and walls - everywhere! Going by last years numbers there should be around 2,000 pairs of Common terns nesting on Rockabill, so you can imagine how careful we have to be when walking around!

We hope to do a full census of the island this week so I'm sure we'll find more nests in unexpected places - we'll keep you updated!

Until then!

- Brian & Donnacha

Wednesday, 4 June 2014

So what's actually on the Bill part of Rockabill?

As of later this week we will have been on Rockabill for a month - and that month has flown by for the pair of us! From the first ten days or so of vegetation management and nestbox deployment, to the comings and goings of the Terns before they all started to settle and lay eggs, with many of them now incubating a full clutch - there's never a boring moment out here and the next two months will no doubt be the same! 

We've been based on the main part of Rockabill i.e. 'the Rock' a.k.a. 'the lighthouse island' because this is where the vast majority of the Terns nest, but today we made the very brief journey across 20m of the Irish Sea to 'the Bill', on a ship (well, an inflatable rubber dinghy..) captained by Dr. Steve Newton (BWI Seabird Conservation Officer, and our boss!).

'The Bill' as seen from 'The Rock'.

We had some curious onlookers as we made our way across the water.

So what's actually on the Bill I hear you ask? Well put it this way - if someone asked you to describe what the lighthouse island is like, one of the first things you'd probably mention is 'rocks'. If someone asked you to describe the Bill, the only thing you'd mention is rocks!  It's a little bit longer and wider than I expected, but it's very very rocky!

Rocks, rocks and more rocks! (and a conservationist or two...)

In terms of avian life there's usually Herring and Great Black-Backed Gulls resting on the west end of the island, with the occasional Cormorant taking a break with their wings outstretched.

Cormorant on the Bill.

There's also a few Black Guillemot nests in various cracks and crevices under boulders, and importantly it's where a significant proportion of Rockabill's Arctic Tern nest. The Arctic Tern migrates to here from the Antarctic Seas - it's one of the longest migrations of any animal (>60,000km) and because it spends so much time in the extreme northern and southern lattitudes it experiences more daylight than any other living creature!

We had a quick look and found 7 scrapes with 1 egg each (Arctic Terns usually only lay 2 eggs), but we'll be back next week when there'll hopefully be a few more.

Artic Tern egg - they're supposedly 'more' blue or olive green than Common Tern eggs, but it's often hard to tell! (Picture taken under NPWS license)

Artic Tern us, it is...... (Picture taken under NPWS license)

In addition to the Arctic Terns a lot of the Rockabill Kittiwakes nest on the Bill too.
Kittwakes nesting on the Bill (Picture taken under NPWS license)

So that was it - a quick check to see what's going on over on the Bill - we'll be back again in the coming weeks to track the progress of the breeding birds over there. We got back in our dinghy, and made our way 'home', under the curious and watchful eye of our local seals - no doubt criticising our rowing technique! 

What's been happening on the Rock? Eggs, Eggs and more Eggs! In our next blog post we hope to try and convey just how crazy things are out here, and next week we should be carrying out a full census of the island to see how many nests are here - so keep an eye out for those posts in the near future!

Until then!
- Brian & Donnacha